Please refer to FIG. 1. FIG. 1 is a block diagram of the driving circuit and the LCD panel in accordance with a prior art. As shown in FIG. 1, the LCD panel module 100 is composed of data lines D1˜Dm and scan lines G1˜Gn arranged in a crisscross pattern. The data voltages of the data lines are provided by a source driver 11, and the scan voltages of the scan lines are provided by a gate driver 12. Each crisscrossed pair of the data lines and the scan lines is applied for controlling a display unit P. The equivalent circuit of each display unit P comprises a thin-film transistor, a storage capacitor Cs and a liquid crystal capacitor Clc. The gates and the sources of the thin-film transistors are connected to the gate line G1˜Gn and the scan line D1˜Dm respectively. And the drains of the thin-film transistors are connected to the storage capacitors Cs.
The conventional way of driving the LCD panel is providing scan voltages at the scan lines G1˜Gn in sequence for turning on the thin-film transistors in sequence, and then providing data voltages at the data lines to charge the storage capacitors Cs and the liquid crystal capacitors Clc through the thin-film transistors in order to deflect the liquid crystal molecule. When the scan voltages of the scan lines G1˜Gn are removed, the thin-film transistors are closed thereby, and the storage capacitors Cs and the liquid crystal capacitors Clc maintain the data voltages.
Commonly, there is a standard of the refresh frequency of the LCD panel, such as 60 frames per second, the driving circuit of the LCD panel has to charge the storage capacitor Cs and the liquid crystal capacitor Clc to a predetermined value in a requested period. However, different sizes of the LCD panels have different pixels with different capacitance and resistance respectively. In the formula iΔt=cΔV, the i represents the value of the current, the Δt represents the charge period, the c represents the capacitance, and the ΔV represents the voltage difference. If the required ΔV for the storage capacitor Cs and the liquid crystal capacitor Clc of the display units of the different size LCD panels should be the same, but the capacitance of the display units of the different size LCD panels are different and the refresh frequencies of the LCD panels are required to be the same. The only way to charge the voltage of the display unit to the predetermined voltage within the requested period is to adjust the value of the charging current.
However, the drive force, such as the value of the charging current, of the LCD driving apparatus in accordance with prior art is fixed for particular LCD panel when being manufactured. In other words, the driving apparatus is only suitable for the particular LCD panel. And it's inconvenient to provide different driving apparatus for different LCD panels respectively.